Heat exchanger tube sheet connection



June 30, '1942.

J. A. COY HEAT EXCHANGER TUBE S HEET CONNECTION Filed- June 11, 1941 w H A h w A Patented June 30, 1942 UNITED STAT HEAT EXCHAN GER TUBE SHEE CONNECTION Joseph A. Coy, Tulsa, Okla. Application June 11, 1941,, Serial No. 397,642 4 Claims. (01. 85-15) The invention relates to connections for connecting cover heads of tube sheets of heat exchangers of the submerged type, and has for its object to provide connecting means between the cover head and the tube sheet constructed in a manner whereby leakage around the connecting bolts, connecting the head to the tube sheet, is positively prevented.

A further object is to connect the cover head to the tube sheet by means of bolts extending through the cover head and partially through the tube sheet, and having their heads disposed in chambers of the cover head, which chambers are sealed by tapered pipe plugs for preventing leakage or passage of any liquid which may pass into the chambers, and at the same time, by using a tapered plug, providing means for sealing the chambers which may be easily tightened in case of leakage around the plug thread.

A further object is to provide a reducer connection between the tube sheet and the bolts, thereby allowing the use of coarser thread connection to thin tube sheets on a larger diameter for increasing the holding connection.

A further object is to provide the inner side of the cover head with spacing and bracing lugs engaging the tube sheet and through which the bolts extend, thereby allowing the bolts to be tightened without placing a breaking strain on the cover head.

A further object is to provide a leak proof connection between a heat exchanger cover head and tube sheet.

With the above and other objects in view the invention resides in the combination and arrangement of parts as hereinafter set forth, shown in the drawing, described and claimed, it being understood that changes in the precise embodiment of the invention may be made within the scope of what is claimed without departing from the spirit of the invention.

In the drawing:

Figure 1 is a detail sectional view through a relatively thin tube sheet and portion of a cover head, showing the reducer connection between the bolt and the tube sheet.

Figure 2 is a view similar to Figure 1 but showing the reducer connection eliminated and a structure particularly adapted for thicker tube sheets.

Figure 3 is a vertical longitudinal sectional view through one end of the exchanger, showing the bolt connections.

Figure 4 is an end view of the exchanger, shown in Figure 3.

Referring to the drawing and particularly'to Figures 2 and 3, the numeral l designates the tube sheet of a conventional form of heat exchanger, and 2 the tubes. It is the usual practice to attach the cover head 3 to the tube sheet by means of bolts threaded through the sheet and cover head, and it has been found, that even where packing is used, the bolt and the metal of the sheet and head have different expansive properties, incident to difierences in metal, consequently leaks develop through the threaded connection. In the present device this difiiculty is overcome. The cover head 3 is provided with a plurality of tapered bosses 4 which engage the adjacent face of the tube sheet for properly spacing the head and bracing the same, and these bosses terminate in chambers 5, in which the bolt heads 6 are received. The bolt heads are preferably of the plug wrench type as shown. The shanks 1 of the bolts are threaded into the threaded recesses 8 of the tube sheet, and it will be seen that when the bolts are tightened the cover head will be securely held in position and any leakage past the thread of the bolt shanks will be into-the recesses 8 which do not extend entirely through the tube sheet. On the other hand any leakage through the bores 9 of the tapered bosses 4 would pass into the chambers 5 where it is positively stopped by the tapered pipe plugs III, which, incident to their tapered form, may be tightened from time to time to insure a leak proof connection. If desired litharge or other plastic material may be placed in the threads of the plugs I 0 for additionally sealing the thread.

In some heat exchangers the tube sheet is relatively thin, for instance as shown at la in V Figure 1, and where this occurs the tapered lugs 4a of the cover head 3 are short and the bolt shanks l are threaded at I l into the reduced end of the reducer connection l2. The enlarged threaded end I3 of the plug I2 is threaded into an enlarged threaded recess [4 in the tube sheet and which recess extends only partially through the sheet. It will be seen in this construction that coarser threads can be used for connecting the plug I2 to the tube sheet as the end [3 is of greater diameter, hence there will be greater gripping surface of the thread, compensating for the shortness of the threaded end l3; otherwise the construction and operation is the same as shown in Figures 2 and 3, and the same numerals pply.

From the above it will be seen that a bolt connection between a cover head and tube sheet is provided, simple in construction and one wherein leakage past thebolt and through the cover head as well as the sheet is prevented, and by using pipe plugs H] any leakage which may develop may be easily stopped by tightening the plugs. The heat exchanger is of the type usually submerged in a tank and the cover plate is additionally attached to the tube sheet at each end of the exchanger by bolts l5 .extending through the cover head and tube sheet,v and the cover head is provided with the usual intake and discharge pipe I6 according to the direction of flow of the fluid.

The invention having been set ..-forth -.what is cover head and having its head disposed in a 20 chamber of thecover .head, a connecting-plug having a large threaded end threaded into .an

.. enlarged threaded recess in the tube, sheet said plug having a reduced threaded aperture into which the bolt is threaded.

2. A device as set forth in claim 1 including a tapered plug threaded into the outer end of the bolt head chamber of the cover head.

3. In a heat exchanger cover head and tube sheet, a connection between said cover head and tube sheet, said connection comprising a bolt extending through the coverhead, a reducer plug 'interposed between the cover head and the tube sheet, said reducer plug having an enlarged threaded end threaded into a recess in the tube sheet and a threaded recess in the other end thereofbf less diameter than the end of the 5mg threaded into the tube sheet, said bolt being-..threaded into said threaded recess in the reducer plug.

4. A -deviceasset forth in claim 3 including a head carried by the bolt and disposed in a re- 'cess in the cover head and a tapered closure threaded into. .the outerend of said chamber.

JOSEPH A. COY. 

